Function update_installed 

pub fn update_installed(
    nodes_dir: &Path,
    store: &Store,
    slug: &str,
    force: bool,
) -> Result<NodeLibraryRow, NodeError>

Overwrite an installed scheme with the catalog’s current version. When force is false and the user has edited the file (mtime > installed_at), returns Refused so the frontend can confirm before clobbering local edits.